Concluding remarks

Secure drinking water for endangered populations is one of the highest priorities during and after natural disasters. This lies at the core of the UNESCO-IHP project Groundwater for Emergency Situations (GWES). The GWES Framework Document was published in the year 2006. The main outcome and publication of the GWES project is this Methodological Guide complemented by case studies.

Another significant aspect of GWES project activities is organising workshops and seminars focused on groundwater in various types of emergency situations in different regions of the world. A series of such workshops has been held, e.g. in Mexico (2004), in India (2005), in Iran (2006), and others are planned.

The GWES project was also introduced to the World Water Forum in Mexico in 2006.

The second phase of the GWES project was approved by the Intergovernmental Council of IHP and included in the Implementation Plan of the IHP-VII (2008–2013). Project activities during the second phase will be focused mainly on an inventory of groundwater bodies resistant to natural and human impacts in selected pilot regions; the development of methodology and legend of a groundwater vul-nerability map depicting emergency groundwater resources; implementation of pilot studies (Orissa State in India affected regularly by storms and floods has been selected) and publication of the (present) GWES Methodological Guide. Cooperation with the UNESCO International Centre for Water Hazard and Risk Management (ICHARM ) established in Tsukuba, Japan, and with UNISDR and UNU-EHS will be developed further within IHP-VII.

Groundwater is a vast global resource and a significant component of the hydrology of water-sheds and river basins. Its occurrence, flow and storage depend upon climate, physiography and geo-logical conditions. Groundwater is a key component of many geogeo-logical and hydrogeochemical processes, and geotechnical conditions, such as soil and rock behaviour. Groundwater also has impor-tant ecological functions, sustaining spring discharges, river-base flows, lakes and wetlands. Mankind has depended on groundwater since times immemorial, accessing the resource through springs and wells. As awareness grew of the value and widespread occurrence of groundwater, its mostly good quality and low vulnerability to environmental influences, its reliability during droughts and other nat-ural disasters and its generally modest development costs, its use has increased significantly in recent decades. In many developing countries groundwater resources support sustainable living and poverty alleviation of rural populations. In arid and semi-arid regions and on islands, groundwater is the most important and safest, if not the only, source of drinking water.

Historically, even up to the present, people have had to face severe drinking water shortages in the immediate aftermath of natural or man-induced catastrophic events - even in highly developed com-munities. When rescue operations have physically secured an endangered population, the most press-ing priority is the supply and distribution of potable water. Emergency situations in drinkpress-ing water supply of varying severity are reported from many parts of the world following floods, droughts, rain-induced landslides, earthquakes or pollution accidents. However, it is often difficult to organise and construct at short notice a replacement water supply when a regular drinking water source has been damaged or even destroyed. The restoration of a supply may take weeks or months.. Where ground-water has become polluted, its remediation may require years. In order to prevent epidemics and miti-gate individual deprivation in the short term, drinking water is often transported to the affected regions in tankers, or imported in large quantities as bottled water. These measures take time to imple-ment, they are expensive and cannot be sustained.As a result, the affected population temporarily is left deprived and disempowered. Access to local groundwater resources that – ideally - have been proven safe and protected by geological and environmental features, and with long residence times makes rescue activities during and after an emergency more rapid and effective. Such emergency resources have to be identified, evaluated and developed as substitutes for drinking water supplies by installing the necessary infrastructure with which to implement promptly their exploitation. They are essential for drinking water security in disaster-prone regions repeatedly affected by destructive events such as flood plains, tectonically active, volcanic or coastal areas, mountain slopes and/or arid zones.

The impact of natural disasters on drinking water sources is felt far more severely in developing coun-tries than by developed, industrial states. The rural populations of developing councoun-tries depend partic-ularly on shallow dug wells for their drinking water. These sources are highly vulnerable to drought, floods and related pollution, and to saline intrusion in coastal aquifers. The loss of such basic and low-cost sources of water for drinking and other purposes affects significantly the social conditions and eco-nomic activities of local populations.

Ongoing global climate variability and change manifest themselves in the increasing frequency of

Introduction

1. Balt Verhagen and Jaroslav Vrba

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G R O U N D W A T E R R E S O U R C E S F O R E M E R G E N C Y S I T U A T I O N S - A M e t h o d o l o g i c a l G u i d e

floods, droughts and other water-related natural disasters, such as landslides and mudflows. There is a growing trend in the occurrence of major natural disasters globally and increasing numbers of people are affected or killed in such events, with the concomitant physical devastation and /or chemical and biological pollution of drinking water supplies. Developing an effective governance policy to reduce risks associated with disasters and the socio-economic vulnerability of populations is therefore needed on both international and national levels. Particularly in regions regularly affected by natural disasters the establishment and implementation of disaster mitigation policy and drinking water risk management planssignificantly reduce or may even eliminate drinking water services failure following catastrophic events. Both these measures support the formulation of effective water governance policyfor emergency situations to manage water resources during and after disasters in an equitable manner.

Introduction

The terrestrial water inventory amounts to about 1.386 x 10⁹km³. Ocean water constitutes about 97.5 vol.% and fresh water the remaining 2.5 vol.%.

Fresh water occurs only because of the water cycle, which links the three big reservoirs on earth, the atmosphere with the lithosphere and the oceans. Solar radiation is the driving force of the water cycle, transformed into heat in the atmosphere and the earth’s surface thus driving evapo-transpiration.

Except for sea-ice at the North Pole, all fresh-water is found on the continents:

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68.9 vol.% is fixed in ice shields, glaciers (27,000,000 km³) and about 300,000 km³ in permafrost (Shiklomanov, 1990),

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29.9 vol.% is groundwater,

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0.9 vol.% is soil moisture and atmospheric water vapour and

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0.3 vol.% appears as surface water. The average groundwater contribution to surface run-off amounts to about 50%; 5 to 10% of subsurface fluxes discharge directly to the oceans. As compared to the water cycle and the mean groundwater recharge on earth, less than 50% of the existing groundwater was recharged within the last 100 years through the present water cycle, the rest was renewed in the historic or geological past under climate conditions which are not known in every detail; hence, groundwater resources evaluation is faced with a variety of water storage forms and run-off systems, changing with time.

At present, more than 40% of the world’s population uses groundwater and about 50% of the world’s food production depends on irrigated agriculture linked to groundwater. Apart from human and ecosystem needs, water plays an important role in distributing and storing energy and matter over the globe and in natural attenuation processes. Fortunately, and in contrast to other geological deposits of economic value, the water cycle drives the renewal of water resources and groundwater flow at various time scales, governed by local or regional orography, tectonics and ocean levels. In temperate and tropical humid climates, groundwater flow is usually at steady state, hence, in balance with present groundwater recharge; in permafrost and arid areas (Loyd, 1980), however, its motion is often transient, or not in balance with the present water cycle. Groundwater management and land use may add a man-made transient behaviour to groundwater flow, which, however, is often not immediately discernible.

Groundwater:

Dans le document EMERGENCY SITUATIONS (Page 35-38)